Biofuel Production Boosted by Plastic Waste: Co-Hydrothermal Liquefaction of Plastic and Biomass toward Sustainable Energy

The continuous rise in the global energy demand is coupled with increasing environmental pollution and greenhouse gas emissions. The need to minimize plastic waste accumulation has driven research into alternative and renewable fuel sources. Co-processing plastic waste and biomass through hydrothermal liquefaction (HTL) has emerged as a promising approach for biofuel production by leveraging the synergistic properties of these feedstocks. This review explores the potential of plastics and biomass for biofuel production, with a focus on recent advances in HTL techniques. The paper delves into the influences of various parameters, such as temperature, pressure, feedstock ratios, and the synergistic potential of combining various plastics with different biomass feedstocks on the bio-oil yield and quality. It also highlights the environmental and economic benefits of HTL, offering insights from life cycle assessments and techno-economic analyses. The review demonstrates that HTL not only unlocks new pathways for renewable energy but also offers an innovative strategy for managing plastic waste, paving the way for a circular and sustainable bio-economy.